How to simulate for mixer iip2 using spectreRF?
it is very confusing me in choosing the second harmonic.
thank you.
hi
as I know you must simulate iip3.
iip2 is not important because this signal can be filtered easily.
regards
for direct conversion receivers the iip2 , is also important
so should be simulated , but i don't know how to simulate it
u can check on ADS design guide it may have some setups
khouly
thank u for ur responses.
ls it so important for low IF receivers also?
yeah , for low IF receivers , the IIP2 is important as well
khouly
Added after 1 hours 25 minutes:
the second order itermodulation if two freq in the RF a , b
if u expand (cos(a)+cos(b))2 = cos(a+b)+cos(a-b)+1/2cos(2a)+1/2cos(2b)
then the term a+b is high freq , but a-b . may generate a frequency near ur cahnnel if it low IF or zero IF
in ur simulation check the power of this spectral compoent
khouly
Hi
Dear khouly
thanks for this information.
yes, I accept that IIP2 is important in this case.
I think that the best way is what he said.
I'm not sure but this equation may help you
IIP3=(3Po-IM3)/2
so
IIP2=(2Po-IM2)/2
regards
i agree with u
how to simulate the Ip2 , make 2 tone , and sweep the input power and then plot the output power of the IM2 term , u and extrapolate the curve to intersect with the gain , this is IIP2
this can be done by any RF simulator
khouly
my problem is in choosing the second harmonic.
all the frequencies (flo - (f1 + or - f2) will fall out of band.
for IIP3 we choose flo-(2f1-f2) as the third harmonic.
ref :http://www.designers-guide.org/Analy...cept-point.pdf
but i dont know how to choose the second harmonic.
thank you..
Hi
If it is out of band then it is not important.
Just in band signals are important.
regards
you should not choose (flo - (f1 + or - f2) as the second harmonic the iip2 frequency should be (f1- f2), i think you can detect the power of (f1- f2) at the if port .and calculate the iip2 use the formula "IIP2=Pin+(Pfund,out-p(f1- f2),out)" .Pfund,out is the power at IF port with the Pin in the RF port ,and p(f1- f2),out is the outout power at (f1- f2) frequency at the IF port.